High aspect ratio ( L/D) riser VIV prediction using wake oscillator model

• Published in: Ocean engineering Vol. 35; no. 17; pp. 1769 - 1774
• Main Authors: Xu, Wan-Hai, Zeng, Xiao-Hui, Wu, Ying-Xiang
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2008; Elsevier
• Subjects: Applied sciences; Aspect ratio; Buildings. Public works; Exact sciences and technology; Hydraulic constructions; Offshore structure (platforms, tanks, etc.); Riser; van der Pol equation; Vortex-induced vibration; Wake oscillator; Wake oscillator; Aspect ratio; Riser; Vortex-induced vibration; van der Pol equation; Van der Pol equation; Two dimensional model; Forecast model; Wake; Experimental result; Vibration effect; Oscillator; Offshore structure; Vortex; Comparative study
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2008.08.015

A two-dimensional (2-D) vortex-induced vibration (VIV) prediction model for high aspect ratio ( L/D) riser subjected to uniform and sheared flow is studied in this paper. The nonlinear structure equations are considered. The near wake dynamics describing the fluctuating nature of vortex shedding is modeled using classical van der Pol equation. A new approach was applied to calibrate the empirical parameters in the wake oscillator model. Compared the predicted results with the experimental data and computational fluid dynamic (CFD) results. Good agreements are observed. It can be concluded that the present model can be used as simple computational tool in predicting some aspects of VIV of long flexible structures.